Video processing device, video display device and video processing method therefor and program thereof

ABSTRACT

In the video processing device, a correction amount update determining unit determines whether to update a correction amount based on an input image obtained from an image input unit and when a cut point is detected or when the number of frames in a number of frames storing unit exceeds a fixed value, determines that update is required, and at this time, a correction amount obtaining unit obtains a new correction amount based on the input image. Then, if no cut point is detected, an amount of change of a correction amount in time is limited and the obtained result is recorded in a correction amount storing unit, and an image correcting unit conducts quality improving correction processing with respect to the input image based on a correction amount recorded in the correction amount storing unit and the image corrected is sent to an image output unit.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a video processing device, avideo display device and a video processing method therefor, and aprogram thereof and, more particularly, to a method of automaticallyimproving quality of a moving image.

[0003] 2. Description of the Related Art

[0004] Image quality improving represents subjecting an original imageto image correction processing so as to make still picture and movingpicture clearer. Among correction processing for improving image qualityare saturation correction and γ (gamma) correction.

[0005] Saturation correction is correction intended to adjust saturationindicative of a density of color. Since people are apt to prefer animage whose saturation is high, saturation correction is often conductedso as to adjust saturation of an original image to be high. γ correctionis correction intended to adjust brightness of an image. People preferimages of appropriate brightness to images too dark or too bright.Adjusting such brightness is γ correction.

[0006] Other than those mentioned above, various kinds of correctionsexist and using these correction processing methods to make an imageclearer is represented as image quality improving processing. As theabove-described image quality improving methods, there conventionallyexist such methods as set forth below.

[0007] For improving quality of a still image, various still picturequality automatic improving techniques have been used. Still picturequality improving techniques here include those recited in “Color ImageQuality Automatic Improvement by Adjustment of Saturation, Contrast, andSharpness” (Inoue and Tajima, the 24th Image Technology ConferenceProceedings 3-3, 1993)(Literature 1), Japanese Patent Laying-Open(Kokai) No. Heisei 09-147098 (Literature 2), Japanese Patent Laying-Open(Kokai) No. Heisei 10-150566 (Literature 3) and “Automatic ColorCorrection Method Realizing Preferable Color Reproduction” (Tsukada,Funayama, Tajima, Color Forum JAPAN 2000 Proceedings, pp. 9-12, 2000)(Literature 4).

[0008] In the automatic image quality improving methods recited in theseliteratures, a certain feature amount is extracted from an input imagecomposed of still images and a correction amount is determined based onthe feature amount to conduct correction for quality improving. Featureamount here represents, for example, an average luminance of a darkregion within a screen or an average tone value of each of RGB (R: red,G: green, B: blue) in a bright region within a screen.

[0009] In the following, one example of each correction method will bedetailed. One example of saturation correction realization methods isshown in FIG. 28. In the present saturation correction realizationmethod, first create a histogram of S values using an HSV (HueSaturation Value) coordinate system or the like with respect to an inputimage illustrated in FIG. 28(a) [see FIG. 28(b)]. The HSV coordinatesystem here is recited in “Color Gamut Transformation Pairs” (A. R.Smith, Computer Graphics, vol. 12, pp. 12-19, 1978).

[0010] An S value in the HSV coordinate system denotes saturation, and ahistogram of S values therefore can be considered as a histogram ofsaturation. In the histogram here generated, assume that a highsaturation portion where an area ratio to the total number of pixels hasa fixed rate “a” is a high saturation region. Then, calculate an averagesaturation SAF of the high saturation region [see FIG. 28(b)]. Calculatea correction amount Copt from the average saturation SAF according tothe following expression:

Copt=SAFopt/SAF  (1)

[0011] where the average saturation SAFopt represents an optimum valuethat a saturation image of an input image can take.

[0012] The larger thus calculated correction amount Copt becomes, themore saturation will be highlighted [see FIG. 28(c)]. The value of c0 inthe figure is that obtained when a range of the saturation S of an inputimage is expanded to the largest and when c=c0, the saturation S of theinput image extends to the largest range as shown in FIG. 28(c) [seeFIG. 28(d)].

[0013] In image quality improving, obtain an S value from an RGB valueof each pixel of a frame image and linearly transform the obtained valueaccording to the following expression:

S′=C0 pt×S  (2).

[0014] After the transformation, restoring the value to an RGB valueagain leads to completion of an image being corrected. Theabove-described saturation correction is recited in Literature 1.

[0015] One example of exposure correction realization methods is shownin FIG. 29. In the present exposure correction realization method, firstcreate a histogram of Y values using an XYZ coordinate system withrespect to an input image illustrated in FIG. 29(a) [see FIG. 29(b)].Since a Y value denotes luminance, the histogram of Y values can beconsidered as a luminance histogram.

[0016] At this time, with all times the number of pixels set to be m,and with a value of the m-th highest luminance as Zmax and a value ofthe m-th lowest luminance as Zmin, obtain an intermediate value M of thehistogram according to the following expression:

M=(Zmax+Zmin)/2  (3).

[0017] A γ value with which the intermediate value M becomes M0, halfthe dynamic range, after the transformation can be obtained by thefollowing expression:

γ=[log(255/M0)]/[log (255/M)]  (4).

[0018] Exposure correction is realized by first obtaining a Y value froman RGB value of each pixel of a frame image and subjecting the inputimage to gamma correction by using a γ value obtained by the expression(4) and the following expression with respect to the obtained Y value[see FIG. 29(c) and (d)]. $\begin{matrix}{Y = {\frac{255}{255^{\gamma}}Y^{\gamma}}} & (5)\end{matrix}$

[0019] As to the above-described exposure correction, recitation isfound in Literature 3.

[0020] One example of white balance correction realization methods isshown in FIG. 30. In the present white balance correction method, firstcreate a luminance histogram with respect to an input image illustratedin FIG. 30(a) using an XYZ coordinate system or the like [see FIG.30(b)].

[0021] At this time, with “a” times the number of pixels set to be m,consider a mean value of the respective tone values of pixels having thehighest to the m-th highest luminances as a white point of the image.With the white point RGB value denoted as (wr, wg, wb) and a white colorRGB value obtained after adjustment as (wr0, Wg0, wb0), obtain whitebalance correction amounts r, g, b according to the followingexpressions:

r=wr0/wr g=wg0/wg b=wb0/wb  (6).

[0022] Based on the above obtained correction amounts and the followingexpressions, linear transformation of each tone value will realize whitebalance correction as illustrated in FIG. 30(c):

R′=r×R G′=g×G B′=b×B  (7).

[0023] As to the above-described white balance correction, recitation isfound in Literature 2.

[0024] One example of contrast correction realization methods is shownin FIG. 31. In the contrast correction realization method, first, createa histogram of Y values, that is, a luminance histogram, with respect toan input image illustrated in FIG. 31(a) using an XYZ coordinate systemor the like [see FIG. 31(b)].

[0025] At this time, with “a” times the number of pixels set to be m,obtain an average luminance Vmax of pixels having the highest to them-th highest luminances. Similarly, obtain an average luminance Vmin ofpixels having the lowest to the m-th lowest luminances [see FIG. 31(b)].

[0026] Based on these values, obtain the following expression which is astraight line passing the coordinates (Vmin, 0), (Vmax, 255):

V′=a×V+b  (8).

[0027] In the expression, V denotes a luminance Y value of a pixel of anoriginal image and V′ denotes a Y value of the pixel transformed. Bylinearly transforming a luminance of each pixel using the expression (8)for the inversion into an RGB value realizes contrast highlighting. Asto the above-described contrast correction, recitation is found inLiterature 1.

[0028] One example of sharpness correction realization methods is shownin FIG. 32. In the present sharpness correction method, first subject aninput image shown in FIG. 32(a) to a high-pass filter to extract an edgecomponent as illustrated in FIG. 32(b). With ss representing a high-passfilter, E(V) representing an edge region, AE(V) representing an area ofan edge region, V representing a luminance and ES0pt representing anoptimum sharpness of the image in question, the sharpness correctionamount k will be obtained by the following expression: $\begin{matrix}{k = \frac{{{ES}_{opi} \cdot {A_{E}( V^{\prime} )}} - {\int{\int_{E{(V^{\prime})}}{{{V \otimes {ss}}}{x}{y}}}}}{\int{\int_{E{(V^{\prime})}}{{{V \otimes {ss} \otimes {ss}}}{x}{y}}}}} & (9)\end{matrix}$

[0029] Using k obtained by the expression (9), the sharpening will beconduced based on the following expression:

V′=V+k(V{circle over (x)})  (10)

[0030] By inversely transforming an RGB value from V′ obtained by theexpression (10), sharpness correction will be realized. As to theabove-described sharpness correction, recitation is found in Literature1.

[0031] One example of preferable color correction realization methods isshown in FIG. 33. Preferable color correction is making look of color ofan image (representing how the color is perceived by a person, which isalso the case in the following description) be more preferable to humaneyes by approximating the color of the image to color of the objectremembered by a person. Specific processing shown in FIG. 33 as anexample is conducted in a manner as follows.

[0032] Calculate a hue of each pixel of a frame image shown in FIG.33(a) to create such a histogram of hues as illustrated in FIG. 33(b).Correct the histogram to make hues related to skin color, color of thesky and green color of plants be those producing more preferable colorsby adapting color correction parameters given in advance according toeach divisional hue region as shown in FIG. 33(c).

[0033] As a result, as illustrated in FIG. 33(d), the image has morepreferable colors with only the colors of skin, the sky and green ofplants changed. Subjecting the image to such processing realizespreferable color correction. The preferable color correction is intendedfor obtaining color that one finds preferable when looking only at acorrected image and is conducted based on the contents of know-howaccumulated in a data base for a long period of time. As to theabove-described preferable color correction, recitation is found inLiterature 4.

[0034] Using such still picture automatic quality improving techniquesas mentioned above realizes quality improving of still picture. Used forimproving quality of a moving image is a method of improving qualityusing a fixed parameter. Fixed parameter is a correction amountparameter fixed to a constant value in order to conduct certaincorrection for a moving image. Fixed parameters are, for example, asfollows.

[0035] As shown in FIG. 34, generate images corrected with γ values asvarious gamma correction parameters in the expression (5) changed andcompare the images to obtain an optimum γ value with which the imagelooks clearer by a subjective evaluation test. At the time of subjectinga moving image to γ correction, when the correction is conducted usingan optimum γ value without changing a γ value, the γ value can beconsidered as a fixed parameter. Technique for improving quality ofimages using such fixed parameter not only in γ correction but also invarious correction processing is employed in moving image qualityimproving processing.

[0036] With the above-described conventional systems in which acorrection amount is given by a fixed parameter, however, the movingimage quality improving techniques fail to appropriately change acorrection amount according to a video source and video shootingconditions.

[0037] Moving image has its image quality largely varying depending onits video source and video shooting conditions. In terms of thedifference in video sources, a moving image obtained from a DVD (DigitalVersatile Disc) deck has high saturation and relatively high contrast,while a moving image shot by an individual person using a home-usedigital video camera or the like has low saturation and low contrast aswell because of properties of cameras.

[0038] In terms of shooting conditions, scenery shot by a digital videocamera in cloudy weather and that shot in fine weather will partiallydiffer in saturation and contrast. Quality of a moving image thus varieslargely depending on circumstances.

[0039] On the other hand, with a correction amount determined by a fixedparameter, while an image taken by a digital video camera is clear, aDVD image might exhibit unnatural look because of too much correction insome cases. Although such a case can be coped with by a method ofobtaining a fixed parameter for each video source and manually switchingand using the parameters according to each video source, the method isnot convenient because it fails to cope with different image qualitiescaused by different shooting conditions and needs manual switching.

SUMMARY OF THE INVENTION

[0040] Under these circumstances, an object of the present invention isto eliminate the above-described shortcomings and provide a videoprocessing device, a video display device and a video processing methodtherefor and a program thereof which enable a correction amount to beappropriately changed according to image quality of an input movingimage and enable quality of a moving image to be automatically improved.

[0041] According to the first aspect of the invention, a videoprocessing device comprises

[0042] correction amount obtaining means for obtaining a correctionamount from sequentially applied moving images, and

[0043] image correcting means for subjecting an input moving image toquality improving correction processing based on a correction amountobtained by the correction amount obtaining means.

[0044] In the preferred construction, the video processing devicefurther comprises image input means for obtaining a frame image fromsequentially applied moving images and outputting the image to thecorrection amount obtaining means, wherein

[0045] the correction amount obtaining means obtains the correctionamount from the frame image and the image correcting means subjects theframe image to quality improving correction processing based on thecorrection amount.

[0046] In another preferred construction, the video processing devicefurther comprises correction region cutting-out means for, before themoving image is subjected to correction processing, cutting out a regionto be corrected from the moving image in question, and

[0047] image composing means for combining a region to be correctedwhich is cut out by the correction region cutting-out means and a regionnot to be corrected which is a remainder left after the region to becorrected in question is cut out.

[0048] In another preferred construction, the video processing devicefurther comprises correction amount change limiting means for limitingan amount of change between a correction amount of a current frame imageobtained by the correction amount obtaining means and a storedcorrection amount of a preceding frame image.

[0049] In another preferred construction, the video processing devicefurther comprises lapse of fixed time detecting means for counting thenumber of frames from a frame image whose the correction amount islastly updated to a current frame image to determine whether the numberof frames exceeds a fixed value, and

[0050] correction amount update determining means for giving aninstruction to update the correction amount when the lapse of fixed timedetecting means determines that a fixed time has elapsed.

[0051] In another preferred construction, the video processing devicefurther comprises cut point detecting means for detecting a cut pointindicative of switching of a scene in the moving image based on a changeof a feature amount obtained from each frame image, and correctionamount update determining means for giving an instruction to update thecorrection amount when the cut point detecting means detects the cutpoint.

[0052] In another preferred construction, the video processing devicefurther comprises lapse of fixed time detecting means for counting thenumber of frames from a frame image whose the correction amount islastly updated to a current frame image to determine whether the numberof frames exceeds a fixed value,

[0053] cut point detecting means for detecting a cut point indicative ofswitching of a scene in the moving image based on a change of a featureamount obtained from each frame image, and

[0054] correction amount update determining means for giving aninstruction to update the correction amount either when detection of alapse of a fixed time is made by the lapse of fixed time detecting meansor when detection of the cut point is made by the cut point detectingmeans.

[0055] In another preferred construction, the correction amountobtaining means includes

[0056] correction amount calculating means for calculating n (n≧1) kindsof arbitrary correction amounts, and

[0057] the image correcting means includes

[0058] n kinds (n≧1) of arbitrary correcting means.

[0059] In another preferred construction, the correction amountobtaining means includes at least one of

[0060] white balance correction amount calculating means for calculatinga white balance correction amount of the moving image,

[0061] contrast correction amount calculating means for calculating acontrast correction amount of the moving image,

[0062] saturation correction amount calculating means for calculating asaturation correction amount of the moving image,

[0063] exposure correction amount calculating means for calculating anexposure correction amount of the moving image,

[0064] sharpness correction amount calculating means for calculating asharpness correction amount of the moving image, and

[0065] preferable color correction amount calculating means forcalculating a preferable color correction amount indicative of acorrection amount required for a preset preferable color in the movingimage, and

[0066] the image correcting means includes at least one of

[0067] white balance correcting means for conducting white balancecorrection of the moving image corresponding to the correction amountobtaining means,

[0068] contrast correcting means for conducting contrast correction ofthe moving image,

[0069] saturation correcting means for conducting saturation correctionof the moving image,

[0070] exposure correcting means for conducting exposure correction ofthe moving image,

[0071] sharpness correcting means for conducting sharpness correction ofthe moving image, and

[0072] preferable color correcting means for conducting the preferablecolor correction of the moving image.

[0073] In another preferred construction, the image correcting meansconducts

[0074] correction with respect to a moving image corrected by the imagecorrecting means at a preceding stage based on a correction amountcalculated by the correction amount obtaining means and the correctionamount obtaining means calculates the correction amount of a movingimage corrected by the image correcting means corresponding to thecorrection amount obtaining means at a preceding stage.

[0075] In another preferred construction, the correction amountobtaining means includes

[0076] an evaluation region cutting-out means for cutting out anevaluation image region for calculating a correction amount from theframe image.

[0077] In another preferred construction, the correction amountobtaining means includes upper limit value adjusting means for comparinga correction amount obtained in advance and an upper limit value andwhen the value is larger than the upper limit value, replacing the valuewith a predetermined set value.

[0078] In another preferred construction, the correction amount changelimiting means includes

[0079] change amount calculating means for calculating an amount ofchange between a latest correction amount and a correction amount of apreceding frame and change amount limiting means for limiting an amountof change of the correction amount based on a maximum change range.

[0080] In another preferred construction, the cut point detecting meansis structured to consider a result of comparison of a color histogramgenerated based on color information of each pixel of the moving imagewhich is conducted on a frame basis as a feature amount and detect a cutpoint of the moving image based on a change of the feature amount.

[0081] In another preferred construction, the cut point detecting meansis structured to, at the time of generating the color histogram from themoving image, generate the color histogram after thinning out the imageat fixed intervals.

[0082] According to the second aspect of the invention, a videoprocessing device comprises

[0083] image input means for obtaining a frame image from sequentiallyapplied moving images, and

[0084] cut point detecting means for detecting a cut point indicative ofswitching of a scene in the moving image based on a change of a featureamount obtained from each frame image.

[0085] In the preferred construction, the cut point detecting means isstructured to consider a result of comparison of a color histogramgenerated based on color information of each pixel of the moving imagewhich is conducted on a frame basis as a feature amount and detect a cutpoint of the moving image based on a change of the feature amount.

[0086] In another preferred construction, the cut point detecting meansis structured to, at the time of generating the color histogram from themoving image, generate the color histogram after thinning out the imageat fixed intervals.

[0087] According to the third aspect of the invention, a video displaydevice comprises

[0088] moving image correction amount obtaining means for obtaining N(N≧1) kinds of correction amounts from sequentially applied movingimages,

[0089] image correcting means for conducting N (N≧1) kinds of qualityimproving corrections with respect to the moving image based on acorrection amount obtained by the moving image correction amountobtaining means, and

[0090] image display means for displaying a moving image corrected bythe image correcting means.

[0091] According to another aspect of the invention, a video processingmethod comprising the steps of

[0092] obtaining a correction amount from sequentially applied movingimages, and

[0093] conducting quality improving correction with respect to theapplied moving image based on the obtained correction amount.

[0094] In the preferred construction, the video processing methodcomprising the steps of

[0095] obtaining a correction amount from each frame image formingsequentially applied moving images, and

[0096] conducting quality improving correction with respect to the frameimage based on the obtained correction amount.

[0097] In another preferred construction, the video processing methodcomprising the steps of

[0098] updating a correction amount for every N frames (N≧1).

[0099] In another preferred construction, the video processing methodcomprising the steps of

[0100] checking the input moving image on a frame basis and when a cutpoint indicative of switching of a scene in the input moving image isdetected, updating a correction amount.

[0101] In another preferred construction, the video processing methodcomprising the steps of

[0102] updating a correction amount for every N frames (N≧1), and

[0103] checking the input moving image on a frame basis and when a cutpoint indicative of switching of a scene in the input moving image isdetected, updating a correction amount.

[0104] In another preferred construction, the video processing methodcomprising the steps of

[0105] obtaining n (n≧1) kinds of arbitrary correction amounts at thetime of obtaining the correction amount from the input moving image, and

[0106] conducting n (N≧1) kinds of arbitrary quality improvingcorrections with respect to the input moving image based on the obtainedcorrection amount.

[0107] In another preferred construction, the correction amountobtaining step includes at least one of the steps of

[0108] calculating a white balance correction amount of the movingimage, calculating a contrast correction amount of the moving image,calculating a saturation correction amount of the moving image,calculating an exposure correction amount of the moving image,calculating a sharpness correction amount of the moving image, andcalculating a preferable color correction amount indicative of acorrection amount required for a preset preferable color in the movingimage, and

[0109] the quality improving correction conducting step includes atleast one of the steps of

[0110] conducting white balance correction of the moving imagecorresponding to the correction amount obtaining step, conductingcontrast correction of the moving image, conducting saturationcorrection of the moving image, conducting exposure correction of themoving image, conducting sharpness correction of the moving image, andconducting the preferable color correction of the moving image.

[0111] In another preferred construction, at the quality improvingcorrection conducting step, correction is conducted with respect to amoving image corrected at the step of conducting quality improvingcorrection at a preceding stage based on a correction amount calculatedat the step of obtaining a correction amount, and

[0112] at the correction amount obtaining step, the correction amount iscalculated from a moving image corrected at the step of conductingquality improving correction corresponding to the step of obtaining acorrection amount at a preceding stage.

[0113] In another preferred construction, the video processing methodfurther comprising the step of

[0114] limiting an amount of change between the obtained correctionamount of a current frame and a stored correction amount of a precedingframe.

[0115] In another preferred construction, the video processing methodfurther comprising the step of

[0116] cutting out an evaluation image region necessary for obtainingthe correction amount from the frame image, and

[0117] obtaining the correction amount from the cut-out evaluationimage.

[0118] In another preferred construction, the video processing methodfurther comprising the step of

[0119] at the detection of the cut point, considering a result ofcomparison of a color histogram generated based on color information ofeach pixel of the frame image which is conducted on a frame basis as afeature amount and detecting a cut point of the moving image based on achange of the feature amount.

[0120] In another preferred construction, the video processing methodfurther comprising the step of

[0121] when detecting the cut point, at the time of generating the colorhistogram from the frame image, generating the color histogram afterthinning out the image at fixed intervals.

[0122] In another preferred construction, the video processing methodfurther comprising the step of

[0123] when a moving image partly flows on such a screen as a screen ofa personal computer, before subjecting the moving image to correctionprocessing, cutting out a region to be corrected from the moving imagein question,

[0124] subjecting the cut-out image to be corrected to image correction,and

[0125] combining the region to be corrected which is subjected to imagecorrection and a region not to be corrected which is a remainder leftafter the region to be corrected in question is cut out to output thecombined image.

[0126] According to a further aspect of the invention, a videoprocessing method comprising the steps of

[0127] obtaining a frame image from sequentially applied moving images,and

[0128] detecting a cut point indicative of switching of a scene in themoving image based on a change of a feature amount obtained from eachframe image.

[0129] In the preferred construction, at the cut point detecting step, aresult of comparison of a color histogram generated based on colorinformation of each pixel of the moving image which is conducted on aframe basis is considered as a feature amount and a cut point of themoving image is detected based on a change of the feature amount.

[0130] In another preferred construction, at the cut point detectingstep, at the time of generating the color histogram from the movingimage, the color histogram is generated after thinning out the image atfixed intervals.

[0131] According to a still further aspect of the invention, a videoprocessing program for controlling a computer to execute videoprocessing, comprising the functions of

[0132] obtaining at least one correction amount from moving imagessequentially applied to the computer,

[0133] comparing the obtained correction amount with a correction amountobtained from at least one of preceding past frames to suppress a changein correction amount, and

[0134] subjecting a frame image to quality improving correction based onthe suppressed correction amount.

[0135] As described in the foregoing, at the determination of acorrection amount of a latest frame, by obtaining an amount of changebetween a correction amount of the latest frame and that of a past frameto minimize an amount of change to a degree that causes no flickeringetc., the present invention enables quality of a moving image to beautomatically improved without exhibiting uncomfortable look such asflickering.

[0136] Since according to the present invention, detection of a cutpoint enables detection of switching of a scene, quality improving canbe conducted with an appropriate correction amount according tovariation of scenes.

[0137] When a scene in a moving image is switched, an image whose lookis different from that of the former image is applied to a system. Thus,when look of an image largely changes, an optimum correction amount foreach image might be changed. Because of having the correction amount asa fixed parameter, the conventional methods fail to conduct correctionof moving images with an appropriate correction amount.

[0138] Since upon detecting switching of a scene, the present inventionis allowed to newly obtain an appropriate correction amountautomatically by a moving image correction amount obtaining unit, it ispossible to conduct correction for improving image quality with anappropriate correction amount for each different scene detected.

[0139] Because according to the present invention, when a cut pointdetection and in-frame correction amount obtaining unit evaluates animage, an evaluation region cut-out unit cuts an evaluation region tohave an arbitrary area, automatic image improving is possibleirrespective of difference in video sources.

[0140] Moving image has a display region largely varying depending onits input source. In a case of a TV image or a game image, the image isdisplayed on the entire region of a TV monitor. On the other hand, in acase of a hi-vision image, films and the like, upper and lower blackzones are displayed to reduce an image display region.

[0141] The image quality improving correction method recited as anexample in the present invention in some cases fails to obtain anappropriate correction amount due to the effect of the black zones. Incontrast correction, for example, in which a correction amount isdetermined based on a dark region of a screen, when the whole of thescreen is used as an evaluation region, the correction amount will bedetermined based on a region of upper and lower black zones to preventoptimum improving of quality of images at other region than the blackzones.

[0142] Also as to the cut point detection exemplified in the presetinvention, a cut point might not be detected appropriately because ofthe effects of the black zone. Using the evaluation region cut-out unitdescribed here, however, solves these problems to enable appropriatecut-out of a scene and enable quality of a moving image to be improvedwith an appropriate correction amount.

[0143] Since according to the present invention, the video processingdevice is structured including a saturation correction unit, an exposurecorrection unit, a white balance correction unit, a contrast correctionunit, a sharpness correction unit and a preferable color correction unitas still picture quality automatic improving techniques independently ofeach other in various combinations, various image quality improvingcorrections can be automatically conducted.

[0144] In addition, incorporation of not only the above-described sixunits but also other image quality improving unit enables the presentinvention to improve quality of a moving image in the same manner as theabove six units do.

[0145] Since in cut point detection according to the present invention,thinned-out images are generated, cut point detection is possibleirrespective of interlace characteristics.

[0146] The present invention is premised on various kinds of images suchas a TV image and a DVD image as an input image. Among these images, twoimages are in some cases seen overlapped with each other in one frame.This is a phenomenon occurring when a video signal as an interlace imagehas 30 frames/sec, while the main moving images has 24 frames/sec. Thedifference in frame rates causes such a phenomenon that two images areseen overlapped with each other in one frame as described above.

[0147] When two images thus overlap with each other, an image of apreceding scene and an image of a succeeding scene are seen overlappedwith other in one frame at a cut point. This results in increasingsimilarity between the preceding and the succeeding frames at the cutpoint to hinder cut point detection which has been described in relationto the above effects in some cases. Therefore, thinning out images toeliminate overlap of images enables cut point detection to be conductedmore satisfactorily.

[0148] According to the present invention, since a moving image regionin an input image can be cut out by a correction region cut-out unit atthe time of image quality improving correction processing and because animage composing unit is provided for restoring cut out moving imagessubjected to image quality improving correction to such arrangement asin an original computer screen, out of an image in which a moving imageflows at a part of a screen such as a computer screen, only the movingimage region can be improved to have high quality and displayed.

[0149] On a computer screen, when an application for displaying movingimages such as a media player is activated, there appears an image inwhich still picture forms a surrounding area and a moving image locallyflows. The correction region cut-out unit cuts out such image into astill picture region and a moving image region. As a result, imagequality improving correction can be made of the moving image regionusing an optimum correction amount.

[0150] Thus, the corrected moving image is combined with the surroundingstill picture region by the image composing unit to have a moving imagewhose quality is improved with a correction amount optimum for a movingimage, while display of the computer screen remains original display.

[0151] Other objects, features and advantages of the present inventionwill become clear from the detailed description given herebelow.

BRIEF DESCRIPTION OF THE DRAWINGS

[0152] The present invention will be understood more fully from thedetailed description given herebelow and from the accompanying drawingsof the preferred embodiment of the invention, which, however, should notbe taken to be limitative to the invention, but are for explanation andunderstanding only.

[0153] In the drawings:

[0154]FIG. 1 is a block diagram showing a structure of a videoprocessing device according to a first embodiment of the presentinvention;

[0155]FIG. 2 is a block diagram showing a detailed structure of acorrection amount obtaining unit illustrated in FIG. 1;

[0156]FIG. 3 is a diagram for use in explaining a method of adjusting acorrection amount by the correction amount obtaining unit illustrated inFIG. 1 using an upper limit value and a set value;

[0157]FIG. 4 is a block diagram showing an example of a detailedstructure of an image correcting unit illustrated in FIG. 1;

[0158]FIG. 5 is a flow chart showing operation of the video processingdevice according to the first embodiment of the present invention;

[0159]FIG. 6 is a flow chart showing operation of the correction amountobtaining unit illustrated in FIG. 1;

[0160]FIG. 7 is a flow chart showing operation of the correction amountobtaining unit illustrated in FIG. 1;

[0161]FIG. 8 is a block diagram showing a structure of a videoprocessing device according to a second embodiment of the presentinvention;

[0162]FIG. 9 is a block diagram showing a detailed structure of acorrection amount change limiting unit illustrated in FIG. 8;

[0163]FIG. 10 is a diagram showing one example of processing conductedby the correction amount change limiting unit illustrated in FIG. 8;

[0164]FIG. 11 is a flow chart showing operation of the video processingdevice according to the second embodiment of the present invention;

[0165]FIG. 12 is a block diagram showing a structure of a videoprocessing device according to a third embodiment of the presentinvention;

[0166]FIG. 13 is a block diagram showing a detailed structure of acorrection amount update determining unit illustrated in FIG. 11;

[0167]FIG. 14 is a block diagram showing a detailed structure of a cutpoint detecting unit illustrated in FIG. 13;

[0168]FIG. 15 is a diagram for use in explaining a color histogram foruse in the cut point detecting unit shown in FIG. 13;

[0169]FIG. 16 is a diagram showing a relationship between transition ofa difference value and a threshold value in an example of feature pointcomparison for use in the cut point detecting unit of FIG. 13;

[0170]FIG. 17 is a flow chart showing operation of the video processingdevice according to the third embodiment of the present invention;

[0171]FIG. 18 is a flow chart showing operation of the correction amountupdate determining unit illustrated in FIG. 12;

[0172]FIG. 19 is a flow chart showing operation of the cut pointdetecting unit illustrated in FIG. 13;

[0173]FIG. 20 is a block diagram showing a structure of a videoprocessing device according to a fourth embodiment of the presentinvention;

[0174]FIG. 21 is a schematic diagram showing processing of the videoprocessing device according to the fourth embodiment of the presentinvention;

[0175]FIG. 22 is a flow chart showing operation of the video processingdevice according to the fourth embodiment of the present invention;

[0176]FIG. 23 is a block diagram showing a structure of a videoprocessing device according to a fifth embodiment of the presentinvention;

[0177]FIG. 24 is a block diagram showing a detailed structure of acorrection amount obtaining unit illustrated in FIG. 23;

[0178]FIG. 25 is a block diagram showing an example of a detailedstructure of an image correcting unit illustrated in FIG. 23;

[0179]FIG. 26 is a block diagram showing a structure of a video displaydevice according to a sixth embodiment of the present invention;

[0180]FIG. 27 is a block diagram showing a structure of a videoprocessing device according to a seventh embodiment of the presentinvention;

[0181]FIG. 28 is a diagram for use in explaining one example ofconventional saturation automatic improving correction;

[0182]FIG. 29 is a diagram for use in explaining one example ofconventional exposure automatic improving correction;

[0183]FIG. 30 is a diagram for use in explaining one example ofconventional white balance automatic improving correction;

[0184]FIG. 31 is a diagram for use in explaining one example ofconventional contrast automatic improving correction;

[0185]FIG. 32 is a diagram for use in explaining one example ofconventional sharpness automatic improving correction;

[0186]FIG. 33 is a diagram for use in explaining one example ofconventional preferable color correction;

[0187]FIG. 34 is a diagram for use in explaining one example of aconventional quality improving technique using a fixed parameter.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0188] The preferred embodiment of the present invention will bediscussed hereinafter in detail with reference to the accompanyingdrawings. In the following description, numerous specific details areset forth in order to provide a thorough understanding of the presentinvention. It will be obvious, however, to those skilled in the art thatthe present invention may be practiced without these specific details.In other instance, well-known structures are not shown in detail inorder to unnecessary obscure the present invention. FIG. 1 is a blockdiagram showing a structure of a video processing device according to afirst embodiment of the present invention. In FIG. 1, the videoprocessing device according to the first embodiment of the presentinvention includes an image input unit 1 to be connected with a DVD(Digital Versatile Disc) player, a computer, a game apparatus, a DV(Digital Video) camera, etc. to obtain a frame image forming an inputmoving image, a data processing device 2 operative by program control, astorage device 3 for storing information and an image output unit 4 foroutputting a corrected frame image to the outside of the device.

[0189] The storage device 3 includes a correction amount storing unit31. The correction amount storing unit 31 stores a latest correctionamount. Correction amounts recorded are, an exposure correction amount,a white balance correction amount, a contrast correction amount, asaturation correction amount, a sharpness correction amount and thelike. Contents to be stored are not limited to those mentioned here butvary with correction processing to be actually executed.

[0190] The data processing device 2 includes a correction amountobtaining unit 21, a correction amount storing unit 22 and an imagecorrecting unit 23. The correction amount obtaining unit 21 calculates acorrection amount from a frame image obtained from the image input unit1. The correction amount storing unit 22 stores the correction amountobtained by the correction amount obtaining unit 21 at the correctionamount storing unit 31.

[0191] The image correcting unit 23 subjects the frame image obtainedfrom the image input unit 1 to quality improving correction using thecorrection amount stored in the correction amount storing unit 31 tooutput the corrected image to the image output unit 4.

[0192]FIG. 2 is a block diagram showing a detailed structure of thecorrection amount obtaining unit 21 illustrated in FIG. 1. In FIG. 2,the correction amount obtaining unit 21 includes an evaluation regioncut-out unit 211, a correction amount calculating unit 212, an upperlimit value adjusting unit 213, an upper limit value storing unit 214and a set value storing unit 215.

[0193] The evaluation region cut-out unit 211 cuts out an evaluationimage region for use in calculating a correction amount from a frameimage. The upper limit value storing unit 214 stores a maximum valuethat each correction amount can take. The set value storing unit 215stores a default value of each correction amount.

[0194] The correction amount calculating unit 212 includes a saturationcorrection amount calculating unit 2121, a white balance correctionamount calculating unit 2122, a contrast correction amount calculatingunit 2123, an exposure correction amount calculating unit 2124, asharpness correction amount calculating unit 2125 and a preferable colorcorrection amount calculating unit 2126. Here, the correction amountcalculating unit 212 may be structured without one or more of thesecorrection amount calculating units. Also, these cited correction amountcalculating units are examples only and other correction amountcalculating unit may be incorporated. In FIG. 2, although the respectivecorrection amount calculating units are illustrated in parallel to eachother, they may sequentially execute their operation in an arbitraryorder.

[0195] The saturation correction amount calculating unit 2121 extracts afeature amount from an image for evaluation which is cut out by theevaluation region cut-out unit 211 to determine a saturation correctionamount based on the feature amount. The white balance correction amountcalculating unit 2122 extracts a feature amount from an image forevaluation cut out by the evaluation region cut-out unit 211 todetermine a white balance correction amount based on the feature amount.

[0196] The contrast correction amount calculating unit 2123 extracts afeature amount from an image for evaluation cut out by the evaluationregion cut-out unit 211 to determine a contrast correction amount basedon the feature amount. The exposure correction amount calculating unit2124 extracts a feature amount from an image for evaluation cut out bythe evaluation region cut-out unit 211 to determine an exposurecorrection amount based on the feature amount.

[0197] The sharpness correction amount calculating unit 2125 extracts afeature amount from an image for evaluation cut out by the evaluationregion cut-out unit 211 to determine a sharpness correction amount basedon the feature amount. The preferable color correction amountcalculating unit 2126 extracts a feature amount from an image forevaluation cut out by the evaluation region cut-out unit 211 todetermine a preferable color correction amount for the correction into apreset preferable color based on the feature amount.

[0198] Here, preferable color correction is intended to realize colorthat one finds preferable when looking only at a corrected image and isconducted based on the contents of know-how accumulated in a data basefor a long period of time. More specifically, correction is conductedsuch that hues related to skin color, color of the sky and green ofplants become hues which produce more preferable colors by adapting acolor correction parameter given in advance according to each divisionalhue region. As a result, more preferable colors are obtained with onlythe colors of skin, the sky and green of plants changed. As to theabove-described preferable color correction, recitation is found inLiterature 4.

[0199] When any of correction amounts obtained by the correction amountcalculating unit 212 exceeds an upper limit value recorded in the upperlimit value storing unit 214, the upper limit value adjusting unit 213converts the amount into a set value stored in the set value storingunit 215.

[0200]FIG. 3 is a diagram for use in explaining a method of adjusting acorrection amount by the correction amount obtaining unit 21 using anupper limit value and a set value. In FIG. 3, when any of the correctionamounts obtained by the correction amount calculating unit 212 exceedsthe upper limit value recorded in the upper limit value storing unit214, the upper limit value adjusting unit 213 converts the amount intothe set value recorded in the set value storing unit 215.

[0201]FIG. 4 is a block diagram showing an example of a detailedstructure of the image correcting unit 23 illustrated in FIG. 1. In FIG.4, the image correcting unit 23 includes a white balance correcting unit231, a contrast correcting unit 232, an exposure correcting unit 233, asaturation correcting unit 234, a sharpness correcting unit 235 and apreferable color correcting unit 236. The order how these correctingunits are arranged is not limited to that illustrated in FIG. 4. Theunit 23 may lack in one or more of these correcting units or may furtherinclude other correcting unit.

[0202] The white balance correcting unit 231 subjects an input frameimage to white balance correction based on a white balance correctionamount among the correction amounts recorded in the correction amountstoring unit 31. The contrast correcting unit 232 subjects an inputframe image to contrast correction based on a contrast correction amountamong the correction amounts recorded in the correction amount storingunit 31.

[0203] The exposure correcting unit 233 subjects an input frame image toexposure correction based on an exposure correction amount among thecorrection amounts recorded in the correction amount storing unit 31.The saturation correcting unit 234 subjects an input frame image tosaturation correction based on a saturation correction amount among thecorrection amounts recorded in the correction amount storing unit 31.

[0204] The sharpness correcting unit 235 subjects an input frame imageto sharpness correction based on a sharpness correction amount among thecorrection amounts recorded in the correction amount storing unit 31.The preferable color correcting unit 236 subjects an input frame imageto preferable color correction based on a preferable color correctionamount among the correction amounts recorded in the correction amountstoring unit 31.

[0205]FIG. 5 is a flow chart showing operation of the video processingdevice according to the first embodiment of the present invention, whileFIGS. 6 and 7 are flow charts showing operation of the correction amountobtaining unit 21 of FIG. 1. With reference to FIGS. 1 to 7, descriptionwill be made of the video processing device according to the firstembodiment of the present invention.

[0206] When the processing is started, the video processing device firstinitializes a storage region, a variable and the like (Step S1 in FIG.5). Thereafter, the video processing device obtains an image to becorrected (Step S2 in FIG. 5), calculates an image correction amountbased on the obtained image (Step S3 in FIG. 5) and stores thecalculated image correction amount (Step S4 in FIG. 5).

[0207] The video processing device subjects the input image to imagecorrection processing based on the calculated correction amount (Step S5in FIG. 5) to output the corrected image (Step S6 in FIG. 5).Subsequently, the video processing device determines whether an image isapplied or not (Step S7 in FIG. 5) and when it is applied, returns toStep S2 to obtain the image and repeat the same processing as thatdescribed above. When no image is applied, the video processing deviceends the processing.

[0208] Upon start of the processing, the correction amount obtainingunit 21 cuts out an evaluation region for obtaining a correction amountfrom the frame image (Step S11 in FIG. 6) and calculates a saturationcorrection amount for the cut out image for evaluation (Step S12 in FIG.6).

[0209] Subsequent to the above-described processing, the correctionamount obtaining unit 21 sequentially calculates an exposure correctionamount (Step S13 in FIG. 6), a white balance correction amount (Step S14in FIG. 6), a contrast correction amount (Step S15 in FIG. 6), asharpness correction amount (Step S 16 in FIG. 6) and a preferable colorcorrection amount (Step S17 in FIG. 6). The order of obtaining therespective correction amounts is not limited thereto. In addition, oneor more of the above-described correction amounts can be omitted orother correction amount may be calculated.

[0210] Next, the correction amount obtaining unit 21 confirms an upperlimit value of the obtained correction amount. First, the correctionamount obtaining unit 21 checks whether the saturation correction amountexceeds an upper limit value (Step S18 in FIG. 6) and when it exceedsthe upper limit value, sets the obtained saturation correction amount atthe set value (Step S19 in FIG. 6) and unless it exceeds the upper limitvalue, the unit uses the previously obtained saturation correctionamount.

[0211] Similarly, the correction amount obtaining unit 21 checks whetherthe exposure correction amount exceeds an upper limit value (Step S20 inFIG. 6) and when it exceeds the upper limit value, sets the obtainedexposure correction amount at a set value (Step S21 in FIG. 6) andunless it exceeds the upper limit value, the unit uses the previouslyobtained exposure correction amount.

[0212] The correction amount obtaining unit 21 checks whether the whitebalance correction amount exceeds an upper limit value (Step S22 in FIG.7) and when it exceeds the upper limit value, sets the obtained whitebalance correction amount at a set value (Step S23 in FIG. 7) and unlessit exceeds the upper limit value, the unit uses the previously obtainedwhite balance correction amount.

[0213] The correction amount obtaining unit 21 checks whether thecontrast correction amount exceeds an upper limit value (Step S24 inFIG. 7) and when it exceeds the upper limit value, sets the obtainedcontrast correction amount at a set value (Step S25 in FIG. 7) andunless it exceeds the upper limit value, the unit uses the previouslyobtained contrast correction amount.

[0214] The correction amount obtaining unit 21 checks whether thesharpness correction amount exceeds an upper limit value (Step S26 inFIG. 7) and when it exceeds the upper limit value, sets the obtainedsharpness correction amount at a set value (Step S27 in FIG. 7) andunless it exceeds the upper limit value, the unit uses the previouslyobtained sharpness correction amount.

[0215] Lastly, the correction amount obtaining unit 21 checks whetherthe preferable color correction amount exceeds an upper limit value(Step S28 in FIG. 7) and when it exceeds the upper limit value, sets theobtained preferable color correction amount at a set value (Step S29 inFIG. 7) and unless it exceeds the upper limit value, the unit uses thepreviously obtained preferable color correction amount. After executingthe foregoing steps, the correction amount obtaining unit 21 ends theprocessing.

[0216] At the time of determining a correction amount of a latest frame,by thus obtaining an amount of change between the correction amount ofthe latest frame and that of a past frame to minimize the amount ofchange to a degree that causes no flickering etc., quality of a movingimage can be automatically improved without exhibiting uncomfortablelook such as flickering.

[0217] Moreover, because when the correction amount obtaining unit 21evaluates an image, an evaluation region can be cut out to have anarbitrary size by the evaluation region cut-out unit 211, the presentembodiment enables automatic quality improving irrespective of a videosource.

[0218] Furthermore, since the video processing device according to thepresent embodiment is allowed to include the saturation correcting unit234, the exposure correcting unit 233, the white balance correcting unit231, the contrast correcting unit 232, the sharpness correcting unit 235and the preferable color correcting unit 236 which are still pictureautomatic quality improving techniques in various combinationsindependently of each other, various kinds of high quality improvingcorrections can be automatically conducted. In addition, not only theabove-described six units but also other high quality improving unit canbe incorporated to improve quality of a moving image in the same manneras the above-described six correcting units do.

[0219]FIG. 8 is a block diagram showing a structure of a videoprocessing device according to a second embodiment of the presentinvention. In FIG. 8, the video processing device according to thesecond embodiment of the present invention has the same structure asthat of the first embodiment of the present invention shown in FIG. 1with the only difference being that the data processing device 5 isprovided with a correction amount change limiting unit 24, in which thesame components are indicated by the same reference numerals. Operationof the same components is also identical to that in the firstembodiment.

[0220] The correction amount change limiting unit 24 compares acorrection amount obtained by the correction amount obtaining unit 21with a correction amount of a preceding frame to change the correctionamount according to the comparison result so as not to make a changeamount exceed a fixed value.

[0221]FIG. 9 is a block diagram showing a detailed structure of thecorrection amount change limiting unit 24 illustrated in FIG. 8. In FIG.9, the correction amount change limiting unit 24 includes a changeamount calculating unit 241, a change amount limiting unit 242 and amaximum change range storing unit 243.

[0222] The maximum change range storing unit 243 stores a maximum amountof allowable change from a correction amount of a preceding frame to acorrection amount of a current frame in successive frame images.

[0223] The change amount calculating unit 241 obtains an absolute valueof a difference between a correction amount of a latest frame obtainedby the correction amount obtaining unit 21 and a correction amount of apreceding frame recorded in the correction amount storing unit 31 toacquire an amount of change in correction amount.

[0224] The change amount limiting unit 242 limits a correction amount ofa current frame such that an amount of change in correction amountcalculated by the change amount calculating unit 241 will not exceed amaximum change range recorded in the maximum change range storing unit243.

[0225]FIG. 10 is a diagram showing one example of processing of thecorrection amount change limiting unit 24 illustrated in FIG. 8. Asillustrated in FIG. 10, the correction amount change limiting unit 24obtains an absolute value of a difference between a new correctionamount and an old correction amount and when the value fails to exceed amaximum change range, outputs the correction amount of the current framewithout modification.

[0226] If the absolute value of the difference exceeds the maximumchange range, the change correction amount change limiting unit 24limits the correction amount of the current frame by making the changeamount meet the maximum change range such that the absolute value of thedifference falls within the change range and outputs the limitedcorrection amount.

[0227]FIG. 11 is a flow chart showing operation of the video processingdevice according to the second embodiment of the present invention. Withreference to FIGS. 8 to 11, description will be made of operation of thevideo processing device according to the second embodiment of thepresent invention. In FIG. 11, since processing operation at Steps S31to S33 and S35 to S38 is the same as that of Steps Si to S7 shown inFIG. 5, no description will be made thereof.

[0228] In the first embodiment of the present invention, when acorrection amount is obtained from an input image, the correction amountis recorded without modification to subject the input image to imagecorrection. On the other hand, in the present embodiment, after acorrection amount is obtained (Step S33 in FIG. 11), an amount of changefrom a correction amount of a preceding frame when the correction amountis used without modification in image correction is limited within afixed value (Step S34 in FIG. 11).

[0229] As described above, in the present embodiment, a correctionamount whose amount of change in time is limited is recorded (Step S35in FIG. 11) and based on the recorded amount, image correction isconducted with respect to the input image (Step S36 in FIG. 11).

[0230] As described in the foregoing, by suppressing an amount of changein time of a correction amount within a range in which no flickering isperceived, the present embodiment eliminates a phenomenon of unnaturallook such as flickering. In other words, automatic improving of qualityof moving images is realized by changing a correction amount by thecorrection amount change limiting unit 24 within a range where noflickering is perceived.

[0231] According to the conventional methods, applying the still picturequality improving techniques to each frame image of a moving imageresults in that a correction amount varies with each frame because imagequality of each frame image slightly differs from each other. When anamount of correction changes largely in frame images adjacent to eachother in time, look of the image changes instantly, so that flickeringis perceived in a corrected moving image. The present embodiment solvesthe present problem.

[0232]FIG. 12 is a block diagram showing a structure of a videoprocessing device according to a third embodiment of the presentinvention. In FIG. 12, the video processing device according to thethird embodiment of the present invention has the same structure as thatof the second embodiment of the present invention shown in FIG. 8 withthe difference being that the data processing device 6 includes acorrection amount update determining unit 25 and a change amount limitexecution determining unit 26 and the storage device 7 includes a numberof frames storing unit 32, in which the same components are indicated bythe same reference numerals. In addition, operation of the counterpartcomponents is the same as that of the second embodiment.

[0233] Upon obtaining an image from the image input unit 1, thecorrection amount update determining unit 25 increments the value of thenumber of frames storing unit 32 by one and detects a cut point from theobtained frame image or when detecting the value of the number of framesstoring unit 32 exceeding a fixed value, determines to update thecorrection amount. In other words, the correction amount updatedetermining unit 25 generates a cut point detection signal whendetecting a cut point and generates a lapse of fixed time signal whendetecting a fixed time elapsing.

[0234] The change amount limit execution determining unit 26 determineswhether to execute the correction amount change limiting unit 24 by asignal received from the correction amount update determining unit 25.More specifically, upon receiving the lapse of fixed time signal fromthe correction amount update determining unit 25, the change amountlimit execution determining unit 26 sends the correction amount obtainedfrom the correction amount obtaining unit 21 to the correction amountchange limiting unit 24 and upon receiving the cut point detectionsignal from the correction amount update determining unit 25, sends thecorrection amount to the correction amount storing unit 22.

[0235]FIG. 13 is a block diagram showing a detailed structure of thecorrection amount update determining unit 25 illustrated in FIG. 12. InFIG. 13, the correction amount update determining unit 25 includes aframe counting unit 251, a cut point detecting unit 252 and a lapse offixed time detecting unit 253.

[0236] When a frame is switched in an input image, the frame countingunit 251 increments the number of frames stored in the number of framesstoring unit 32 by one. The cut point detecting unit 252 extracts afeature amount from the input image and compares the feature amount witha feature amount extracted from a preceding frame to detect a cut point.Upon detection of a cut point, the frame counting unit 251 outputs thecut point detection signal to reset the number of frames storing unit32.

[0237] The lapse of fixed time detecting unit 253 checks the number offrames stored in the number of frames storing unit 32 to find whetherthe number exceeds a fixed value. Upon detecting the fixed timeelapsing, the lapse of fixed time detecting unit 253 outputs the lapseof fixed time signal to reset the number of frames storing unit 32.

[0238]FIG. 14 is a block diagram showing a detailed structure of the cutpoint detecting unit 252 of FIG. 13. In FIG. 14, the cut point detectingunit 252 includes an evaluation region cut-out unit 2521, an imagethinning out unit 2522, a histogram generating unit 2523, a histogramcomparing unit 2524 and a histogram storing unit 2525.

[0239]FIG. 15 is a diagram for use in explaining a color histogram foruse in the cut point detecting unit 252 of FIG. 13, while FIG. 16 is adiagram showing a relationship between transition of a difference valueand a threshold value in the example of comparison in feature pointsused in the cut point detecting unit 252 of FIG. 13. With reference toFIGS. 14 to 16, operation of the cut point detecting unit 252 will bedescribed.

[0240] The evaluation region cut-out unit 2521 cuts out an image regionfor use in cut point detection from an input frame image. The imagethinning out unit 2522 extracts every n pixels (n≧1) from the image cutout by the evaluation region cut-out unit 2521 and combines theextracted pixels to generate a thinned out image.

[0241] The histogram generating unit 2523 generates a color histogrambased on color information of each pixel of the input frame image. Colorhistogram is, as illustrated in FIG. 15, a histogram generatedindependently for each of the RGB values as color information of eachpixel of the frame image.

[0242] The histogram storing unit 2525 stores a histogram extracted froma preceding frame. The histogram comparing unit 2524 compares the colorhistogram generated by the histogram generating unit 2523 and the colorhistogram of the preceding frame stored in the histogram storing unit2525 to determine whether a cut point exists between the frames based onthe obtained feature amounts.

[0243] Although used here as histogram comparison processing conductedby the histogram comparing unit 2524 are techniques using a differencevalue and a correlation value of a histogram and the like, thetechniques are not specifically limited. Description will be here madeof a case where a difference value of a histogram is used.

[0244] With a difference value of a histogram used, as a frame changes,its difference value changes as shown in FIG. 16. Between frames where acut point exists, its difference value is apt to be larger than otherpoints. Therefore, as illustrated in FIG. 16, by providing a thresholdvalue to classify the points into a cut point when a difference value islarger than the threshold value and into a non-cut point when the sameis smaller, cut point detection is enabled. This cut point detectionmethod is applicable not only to such video processing as in the presentembodiment but also to compression of images, generation of a digestfrom video and the like.

[0245]FIG. 17 is a flow chart showing operation of the video processingdevice according the third embodiment of the present invention. Withreference to FIGS. 12, 13 and 17, description will be made of the videoprocessing device according to the third embodiment of the presentinvention. Since processing operation at Steps S41, S42, S46, S48, S49and S50 to S52 is the same as that at Steps S31 to S38 in FIG. 11, nodescription will be made thereof.

[0246] In the second embodiment of the present invention, when acorrection amount is obtained from an input image, a range of an amountof allowable change between the obtained correction amount and acorrection amount obtained from a preceding frame is limited. On theother hand, in the present embodiment, first add one to the framecounting unit 251 every time a new frame image is input (Step S43 inFIG. 17).

[0247] In the present embodiment, when detecting a cut point in an inputimage or when the count of the frame counting unit 251 exceeds a fixedvalue, determination is made to update a correction amount (Step S44 inFIG. 17). When the correction amount will not be updated, imagecorrection is conducted using a current correction amount (Step S50 inFIG. 17).

[0248] When the correction is to be updated, reset the frame countingunit 251 to 0 (Step S45 in FIG. 17) to obtain a correction amount fromthe current frame image (Step S46 in FIG. 17). At this time, when a cutpoint has been detected (Step S47 in FIG. 17), record the correctionamount here (Step S49 in FIG. 17) to conduct image correction. When nocut point has been detected (Step S47 in FIG. 17), limit the amount ofchange in a correction amount (Step S48 in FIG. 17) and record thecorrection amount whose change amount is limited (Step S49 in FIG. 17)to conduct image correction.

[0249]FIG. 18 is a flow chart showing operation of the correction amountupdate determining unit 25 illustrated in FIG. 12. With reference toFIGS. 12, 13 and 18, description will be made of operation of thecorrection amount update determining unit 25.

[0250] Upon start of the processing, the correction amount updatedetermining unit 25 increments the frame counting unit 251 by one (StepS61 in FIG. 18) to check whether a cut point exists or not based on theframe image (Step S62 in FIG. 18).

[0251] The correction amount update determining unit 25 checks whether acut point is detected or not (Step S63 in FIG. 18) and if it isdetected, outputs the cut point detection signal (Step S64 in FIG. 18)to reset the frame counting unit 251 to 0 (Step S67 in FIG. 18) andshifts the processing to the correction amount obtaining unit 21.

[0252] When no cut point is detected, the correction amount updatedetermining unit 25 checks whether the count of the frame counting unit251 exceeds a fixed value or not (Step S65 in FIG. 18) and if it exceedsthe fixed value, outputs a fixed time detection signal (Step S66 in FIG.18) to set the frame counting unit 251 to 0 (Step S67 in FIG. 18) andshifts the processing to the correction amount obtaining unit 21. Upondetermining that the count exceeds the fixed value, the correctionamount update determining unit 25 shifts the processing directly to theimage correcting unit 23.

[0253]FIG. 19 is a flow chart showing operation of the cut pointdetecting unit 252 illustrated in FIG. 13. With reference to FIGS. 13,14 and 19, description will be made of operation of the cut pointdetecting unit 252.

[0254] Upon start of the processing, the cut point detecting unit 252cuts out an image region for use in detecting a cut point from a frameimage (Step S71 in FIG. 19), extracts every n pixels (n≧0) from thecut-out image and combines the extracted pixels to form a thinned outimage (Step S72 in FIG. 19).

[0255] The cut point detecting unit 252 generates a histogram based onthe thinned-out image (Step S73 in FIG. 19) and compares the histogramwith a histogram of a preceding frame (Step S74 in FIG. 19).

[0256] Based on the result of the comparison, the cut point detectingunit 252 checks whether a cut point is detected or not (Step S75 in FIG.19), and when it is detected, outputs the cut point detection signal(Step S76 in FIG. 19) and records the histogram generated by the presentprocessing (Step S77 in FIG. 19) to end the processing.

[0257] In the present embodiment, since detection of a cut point enablesdetection of switching of a scene, quality improving can be conductedwith an appropriate correction amount according to different scenes.

[0258] When a scene in a moving image is switched, an image whose lookdiffers from that of preceding images is applied to the system. Whenlook of an image thus changes largely, a correction amount appropriatefor each image might change in some cases.

[0259] With conventional methods, correction of a moving image with anappropriate correction amount is impossible because they use acorrection amount as a fixed parameter. On the other hand, according tothe present invention, when switching of a scene is detected, a newappropriate correction amount is automatically obtained by thecorrection amount obtaining unit 21. Therefore, quality improving can beconducted with an appropriate correction amount according to eachdifferent scene detected.

[0260] Moving image has a display region largely differing with itsinput source. In TV images and game images, images are displayed in theentire area of a TV monitor. On the other hand, in hi-vision images,films, etc., black zones are displayed at upper and lower regions tohave a smaller image display region.

[0261] In the present embodiment, there occurs a case where due to theblack zone, an appropriate correction amount can not be obtained. Incontrast correction, for example, a correction amount is determinedbased on a dark region of a screen. When the whole of the screen is usedas an evaluation region, a correction amount will be determined based onthe region of upper and lower black zones to disable appropriateimproving of quality of an image at other region than the black zones.

[0262] Similarly in cut point detection, a cut point might not bedetected appropriately due to the effect of the black zones in somecases. It is, however, possible by the use of the here describedevaluation region cut-out unit 211 to solve these problems and toappropriately cut a scene to improve quality of a moving image with anappropriate correction amount.

[0263] Since according to the present invention, thinned-out images aregenerated at the time of cut point detection, a cut point can bedetected irrespective of interlace characteristics. In the presentembodiment, it is premised that various kinds of images such as a TVimage and a DVD image exist as an input image. Among these images, twoimages are seen overlapped with each other in one frame in some cases.This is a phenomenon occurring when a video signal as an interlace imagehas 30 frames/sec, while the main moving image has 24 frames/sec. Thedifference in frame rates causes such a phenomenon that two images areseen overlapped with each other in one frame.

[0264] When two images thus overlap with each other as described above,an image of a preceding scene and an image of a succeeding scene areseen overlapped with each other in one frame at a cut point. Thisresults in increasing similarity between the preceding and thesucceeding frames at the cut point to hinder the above-described cutpoint detection in some cases. Therefore, thinning out images toeliminate overlap of images enables cut point detection to be conductedmore satisfactorily.

[0265]FIG. 20 is a block diagram showing a structure of a videoprocessing device according to a fourth embodiment of the presentinvention. In FIG. 20, the video processing device according to thefourth embodiment of the present invention has the same structure asthat of the first embodiment of the present invention shown in FIG. 1with the only difference being that the data processing device 8 isprovided with a correction region cut-out unit 27 and an image composingunit 28, in which the same components are indicated by the samereference numerals. Operation of the counterpart components is the sameas that of the first embodiment of the present invention.

[0266]FIG. 21 is a schematic diagram showing processing of the videoprocessing device according to the fourth embodiment of the presentinvention. With reference to FIG. 21, the correction region cut-out unit27 and the image composing unit 28 will be described.

[0267] The correction region cut-out unit 27, as illustrated in FIG.21(a), cuts out a region to be corrected from an image in which a movingimage partly flows into such a cut-out image as shown in FIG. 21(b) andsuch an image of a region not to be corrected as shown in FIG. 21(e).The cut-out image shown in FIG. 21(b) will have its quality improved asillustrated in FIG. 21(c) by the quality improving technique describedin the first embodiment of the present invention.

[0268] The image composing unit 28 combines the image of a region not tobe corrected which is cut out by the correction region cut-out unit 27and the image being corrected to generate such an input image as shownin FIG. 21(d). Here, the generated image is output from the image outputunit 4 to end the processing.

[0269]FIG. 22 is a flow chart showing operation of the video processingdevice according to the fourth embodiment of the present invention. Withreference to FIGS. 20 to 22, operation of the video processing deviceaccording to the fourth embodiment of the present invention will bedescribed. Since processing operation at Steps S81, S82, S84 to 86, S88and S89 is the same as that of the processing operation at Steps Si toS7 of FIG. 5, no description will be made thereof.

[0270] In the first embodiment of the present invention, the whole of aninput image is corrected as a region to be corrected. On the other hand,in the present embodiment, first cut out a region where a moving imageis displayed from an input image (Step S83 in FIG. 22).

[0271] In the present embodiment, obtain a correction amount for the cutout image (Step S84 in FIG. 22) to subject only the cut out image tocorrection processing based on the obtained correction amount (Step S86in FIG. 22). The corrected image is combined with a region not to becorrected which is an image left after the region to be corrected is cutout (Step S87 in FIG. 22) to form the same screen as that of theoriginal image. In the present embodiment, the present processing willbe repeated until no further image is input.

[0272] Because at the time of executing quality improving correctionprocessing, the correction region cut-out unit 27 is allowed to cut outa moving image region from an input image and also because the imagecomposing unit 28 is provided to restore a cut-out moving image which isfurther subjected to quality improving correction to such arrangement asshown in an original computer screen, the present invention enablesquality improving and display of only a moving image region of an imagein which a moving image partly flows such as a computer screen.

[0273] Upon activation of such an application for displaying a movingimage as a media player on a computer screen, an image appears in whichstill picture forms a surrounding area and a moving image flows locally.With respect to such an image, the correction region cut-out unit 27cuts the image into a region of still picture and a region of a movingimage. As a result, quality improve correction can be conducted withrespect to the moving image region using an appropriate correctionamount. Thus, the corrected moving image is combined with the stillpicture region at the surroundings by the image composing unit 28 toobtain a moving image whose quality is improved by a correction amountappropriate for a moving image, while maintaining such display as thaton an original computer screen.

[0274]FIG. 23 is a block diagram showing a structure of a videoprocessing device according to a fifth embodiment of the presentinvention. In FIG. 23, the video processing device according to thefifth embodiment of the present invention has the same structure as thatof the first embodiment of the present invention shown in FIG. 1 withthe only difference being that in the data processing device 9, an imagecorrected by an image correcting unit 30 is returned to a correctionamount obtaining unit 29, in which the same components are indicated bythe same reference numerals. In addition, operation of the counterpartcomponents is the same as that of the first embodiment of the presentinvention.

[0275]FIG. 24 is a block diagram showing a detailed structure of thecorrection amount obtaining unit 29 illustrated in FIG. 23. In FIG. 24,the correction amount obtaining unit 29 has the same structure as thatof the correction amount obtaining unit 21 shown in FIG. 2 with the onlydifference being that it is designed to input an image corrected by theimage correcting unit 30 to the evaluation region cut-out unit 211, inwhich the same components are indicated by the same reference numerals.In addition, operation of the counterpart components is the same as thatof the correction amount obtaining unit 21.

[0276]FIG. 25 is a block diagram showing an example of a detailedstructure of the image correcting unit 30 illustrated in FIG. 23. InFIG. 25, the image correcting unit 30 has the same structure as that ofthe image correcting unit 23 shown in FIG. 4 with the only differencebeing that a corrected image buffer 237 is provided, in which the samecomponents are indicated by the same reference numerals. In addition,operation of the counterpart components is the same as that of the imagecorrecting unit 23.

[0277] With reference to FIGS. 23 to 25, description will be made ofcharacteristic operation of the video processing device according to thefifth embodiment of the present invention. Being structured to return animage corrected by the image correcting unit 30 to the correction amountobtaining unit 29, the video processing device according to the fifthembodiment of the present invention corrects an image by each correctionunit of the image correcting unit 30 based on a correction amountobtained by each calculation unit of the correction amount obtainingunit 29 and obtains a correction amount from the corrected image by eachcalculation unit of the correction amount obtaining unit 29.

[0278] More specifically, first, the saturation correcting unit 234corrects an input image based on a correction amount obtained by thesaturation correction amount calculating unit 2121 and temporarilyaccumulates the corrected image in the corrected image buffer 237, aswell as returning the corrected image to the correction amount obtainingunit 29.

[0279] Subsequently, the white balance correction amount calculatingunit 2122 obtains a correction amount from the corrected image obtainedby the saturation correcting unit 234. The white balance correcting unit231 corrects the corrected image which is obtained by the saturationcorrecting unit 234 and temporarily accumulated at the corrected imagebuffer 237 based on the correction amount obtained by the white balancecorrection amount calculating unit 2122 to temporarily accumulate thecorrected image at the corrected image buffer 237, as well as returningthe corrected image to the correction amount obtaining unit 29.

[0280] In the same manner as described above, the contrast correctionamount calculating unit 2123 obtains a correction amount from thecorrected image obtained by the white balance correcting unit 231. Thecontrast correcting unit 232 corrects the corrected image which isobtained by the white balance correcting unit 231 and temporarilyaccumulated at the corrected image buffer 237 based on the correctionamount obtained by the contrast correction amount calculating unit 2123to temporarily accumulate the obtained corrected image in the correctedimage buffer 237, as well as returning the corrected image to thecorrection amount obtaining unit 29.

[0281] The exposure correction amount calculating unit 2124 obtains acorrection amount from the corrected image obtained by the contrastcorrecting unit 232. The exposure correcting unit 233 corrects thecorrected image which is obtained by the contrast correcting unit 232and temporarily accumulated at the corrected image buffer 237 based onthe correction amount obtained by the exposure correction amountcalculating unit 2124 to temporarily accumulate the obtained correctedimage in the corrected image buffer 237, as well as returning thecorrected image to the correction amount obtaining unit 29.

[0282] The sharpness correction amount calculating unit 2125 obtains acorrection amount from the corrected image obtained by the exposurecorrecting unit 233. The sharpness correcting unit 235 corrects thecorrected image which is obtained by the exposure correcting unit 233and temporarily accumulated at the corrected image buffer 237 based onthe correction amount obtained by the sharpness correction amountcalculating unit 2125 to temporarily accumulate the obtained correctedimage at the corrected image buffer 237, as well as returning thecorrected image to the correction amount obtaining unit 29.

[0283] The preferable color correction amount calculating unit 2126obtains a correction amount from the corrected image obtained by thesharpness correcting unit 235. The preferable color correcting unit 236corrects the corrected image which is obtained by the sharpnesscorrecting unit 235 and temporarily accumulated at the corrected imagebuffer 237 based on the correction amount obtained by the preferablecolor correction amount calculating unit 2126 to temporarily accumulatethe obtained corrected image at the corrected image buffer 237, as wellas returning the corrected image to the correction amount obtaining unit29.

[0284] By thus conducting correction by each correction unit of theimage correcting unit 30 based on a correction amount obtained by eachcalculation unit of the correction amount obtaining unit 29 andobtaining a correction amount from the corrected image by means of eachcalculation unit of the correction amount obtaining unit 29, an inputimage can be appropriately corrected. The order of arrangement of theabove-described correction amount calculating units and the correctingunits is not limited to those shown in FIGS. 24 and 25. Any one or moreof the correction amount calculating units and the correcting units canbe omitted or other unit may be added. In this case, deletion andaddition of the above-described units are executed in a pair of thecorrection amount calculating unit and the correcting unit.

[0285]FIG. 26 is a block diagram showing a structure of a video displaydevice according to a sixth embodiment of the present invention. In FIG.26, the video display device according to the sixth embodiment of thepresent invention is a device using the above-described video processingdevice and composed of an image input unit 1 and an image displayapparatus 10.

[0286] The image input unit 1 is the same as that of the firstembodiment of the present invention. The image display apparatus 10includes a data processing device 2, a storage device 3 and an imagedisplay unit (monitor) 11. Here, the data processing device 2 and thestorage device 3 are the same as those of the first embodiment of thepresent invention. The image display unit 11 is a CRT (cathode-ray tube)monitor, a liquid crystal monitor or the like.

[0287] When moving image data is applied through the image input unit 1,similarly to the processing by the first embodiment of the presentinvention, the data processing device 2 and the storage device 3 conductsuch correction as white balance correction, contrast correction,exposure correction, saturation correction, sharpness correction and thelike with respect to the moving image to improve the quality of theimage. Here, as to correction given to an image, not all the five kindsof corrections described here needs to be conducted and other correctionthan the corrections mentioned above, and such quality improvecorrection as preferable color correction may be added. Image subjectedto this correction to have its quality improved is displayed on theimage display unit 11.

[0288]FIG. 27 is a block diagram showing a structure of a videoprocessing device according to a seventh embodiment of the presentinvention. In FIG. 27, the video processing device according to theseventh embodiment of the present invention includes a recording medium15 which records a program of the above-described video processingmethod.

[0289] More specifically, the video processing device according to theseventh embodiment of the present invention includes a video inputdevice 12 for receiving input of a moving image, a personal computer(hereinafter referred to as PC) 13 for processing a program, an imagedisplay device 14 for displaying a processing result and the recordingmedium 15 storing the program which is executed by the PC 13 andrealizes the above-described video processing method.

[0290] When a moving image is applied to the PC 13 through the videoinput device 12, the PC 13 executes correction with respect to themoving image based on the program of the video processing method forautomatically improving quality of a moving image which is recorded inthe recording medium 15. The corrected moving image is sent to the imagedisplay device 14 and displayed thereon.

[0291] As described in the foregoing, according to the presentinvention, at the time of improving quality of sequentially appliedvideo, by obtaining a correction amount from each frame image formingthe input moving image in order to conduct quality improve correction ofthe input moving image and by subjecting the frame image to qualityimprove correction based on the obtained correction amount, a correctionamount can be changed appropriately according to quality of an inputmoving image to automatically improve quality of the moving image.

[0292] Although the invention has been illustrated and described withrespect to exemplary embodiment thereof, it should be understood bythose skilled in the art that the foregoing and various other changes,omissions and additions may be made therein and thereto, withoutdeparting from the spirit and scope of the present invention. Therefore,the present invention should not be understood as limited to thespecific embodiment set out above but to include all possibleembodiments which can be embodies within a scope encompassed andequivalents thereof with respect to the feature set out in the appendedclaims.

What is claimed is:
 1. A video processing device comprising: correctionamount obtaining means for obtaining a correction amount fromsequentially applied moving images, and image correcting means forsubjecting an input moving image to quality improving correctionprocessing based on a correction amount obtained by said correctionamount obtaining means.
 2. The video processing device as set forth inclaim 1, further comprising image input means for obtaining a frameimage from sequentially applied moving images and outputting the imageto said correction amount obtaining means, wherein said correctionamount obtaining means obtains said correction amount from said frameimage and said image correcting means subjects said frame image toquality improving correction processing based on said correction amount.3. The video processing device as set forth in claim 1, furthercomprising: correction region cutting-out means for, before said movingimage is subjected to correction processing, cutting out a region to becorrected from the moving image in question, and image composing meansfor combining a region to be corrected which is cut out by saidcorrection region cutting-out means and a region not to be correctedwhich is a remainder left after the region to be corrected in questionis cut out.
 4. The video processing device as set forth in claim 2,further comprising correction amount change limiting means for limitingan amount of change between a correction amount of a current frame imageobtained by said correction amount obtaining means and a storedcorrection amount of a preceding frame image.
 5. The video processingdevice as set forth in claim 2, further comprising: lapse of fixed timedetecting means for counting the number of frames from a frame imagewhose said correction amount is lastly updated to a current frame imageto determine whether the number of frames exceeds a fixed value, andcorrection amount update determining means for giving an instruction toupdate said correction amount when said lapse of fixed time detectingmeans determines that a fixed time has elapsed.
 6. The video processingdevice as set forth in claim 2, further comprising: cut point detectingmeans for detecting a cut point indicative of switching of a scene insaid moving image based on a change of a feature amount obtained fromeach frame image, and correction amount update determining means forgiving an instruction to update said correction amount when said cutpoint detecting means detects said cut point.
 7. The video processingdevice as set forth in claim 2, further comprising: lapse of fixed timedetecting means for counting the number of frames from a frame imagewhose said correction amount is lastly updated to a current frame imageto determine whether the number of frames exceeds a fixed value, cutpoint detecting means for detecting a cut point indicative of switchingof a scene in said moving image based on a change of a feature amountobtained from each frame image, and correction amount update determiningmeans for giving an instruction to update said correction amount eitherwhen detection of a lapse of a fixed time is made by said lapse of fixedtime detecting means or when detection of said cut point is made by saidcut point detecting means.
 8. The video processing device as set forthin 1, wherein said correction amount obtaining means includes correctionamount calculating means for calculating n (n≧1) kinds of arbitrarycorrection amounts, and said image correcting means includes n kinds(n≧1) of arbitrary correcting means.
 9. The video processing device asset forth in claim 2, wherein said correction amount obtaining meansincludes at least one of: white balance correction amount calculatingmeans for calculating a white balance correction amount of said movingimage, contrast correction amount calculating means for calculating acontrast correction amount of said moving image, saturation correctionamount calculating means for calculating a saturation correction amountof said moving image, exposure correction amount calculating means forcalculating an exposure correction amount of said moving image,sharpness correction amount calculating means for calculating asharpness correction amount of said moving image, and preferable colorcorrection amount calculating means for calculating a preferable colorcorrection amount indicative of a correction amount required for apreset preferable color in said moving image, and said image correctingmeans includes at least one of: white balance correcting means forconducting white balance correction of said moving image correspondingto said correction amount obtaining means, contrast correcting means forconducting contrast correction of said moving image, saturationcorrecting means for conducting saturation correction of said movingimage, exposure correcting means for conducting exposure correction ofsaid moving image, sharpness correcting means for conducting sharpnesscorrection of said moving image, and preferable color correcting meansfor conducting said preferable color correction of said moving image.10. The video processing device as set forth in claim 9, wherein saidimage correcting means conducts correction with respect to a movingimage corrected by the image correcting means at a preceding stage basedon a correction amount calculated by said correction amount obtainingmeans and said correction amount obtaining means calculates saidcorrection amount of a moving image corrected by the image correctingmeans corresponding to the correction amount obtaining means at apreceding stage.
 11. The video processing device as set forth in claim9, wherein said correction amount obtaining means includes an evaluationregion cutting-out means for cutting out an evaluation image region forcalculating a correction amount from said frame image.
 12. The videoprocessing device as set forth in claim 9, wherein said correctionamount obtaining means includes upper limit value adjusting means forcomparing a correction amount obtained in advance and an upper limitvalue and when the value is larger than said upper limit value,replacing the value with a predetermined set value.
 13. The videoprocessing device as set forth in claim 4, wherein said correctionamount change limiting means includes change amount calculating meansfor calculating an amount of change between a latest correction amountand a correction amount of a preceding frame and change amount limitingmeans for limiting an amount of change of said correction amount basedon a maximum change range.
 14. The video processing device as set forthin claim 6, wherein said cut point detecting means is structured toconsider a result of comparison of a color histogram generated based oncolor information of each pixel of said moving image which is conductedon a frame basis as a feature amount and detect a cut point of saidmoving image based on a change of the feature amount.
 15. The videoprocessing device as set forth in claim 14, wherein said cut pointdetecting means is structured to, at the time of generating said colorhistogram from said moving image, generate said color histogram afterthinning out the image at fixed intervals.
 16. A video processing devicecomprising: image input means for obtaining a frame image fromsequentially applied moving images, and cut point detecting means fordetecting a cut point indicative of switching of a scene in said movingimage based on a change of a feature amount obtained from each frameimage.
 17. The video processing device as set forth in claim 16, whereinsaid cut point detecting means is structured to consider a result ofcomparison of a color histogram generated based on color information ofeach pixel of said moving image which is conducted on a frame basis as afeature amount and detect a cut point of said moving image based on achange of the feature amount.
 18. The video processing device as setforth in claim 17, wherein said cut point detecting means is structuredto, at the time of generating said color histogram from said movingimage, generate said color histogram after thinning out the image atfixed intervals.
 19. A video display device comprising: moving imagecorrection amount obtaining means for obtaining N (N≧1) kinds ofcorrection amounts from sequentially applied moving images, imagecorrecting means for conducting N (N≧1) kinds of quality improvingcorrections with respect to said moving image based on a correctionamount obtained by said moving image correction amount obtaining means,and image display means for displaying a moving image corrected by saidimage correcting means.
 20. A video processing method comprising thesteps of: obtaining a correction amount from sequentially applied movingimages, and conducting quality improving correction with respect to saidapplied moving image based on the obtained correction amount.
 21. Thevideo processing method as set forth in claim 20, comprising the stepsof: obtaining a correction amount from each frame image formingsequentially applied moving images, and conducting quality improvingcorrection with respect to said frame image based on the obtainedcorrection amount.
 22. The video processing method as set forth in claim20, comprising the step of updating a correction amount for every Nframes (N≧1).
 23. The video processing method as set forth in claim 20,comprising the step of checking said input moving image on a frame basisand when a cut point indicative of switching of a scene in said inputmoving image is detected, updating a correction amount.
 24. The videoprocessing method as set forth in claim 20, comprising the steps of:updating a correction amount for every N frames (N≧1), and checking saidinput moving image on a frame basis and when a cut point indicative ofswitching of a scene in said input moving image is detected, updating acorrection amount.
 25. The video processing method as set forth in claim20, comprising the steps of: obtaining n (n≧1) kinds of arbitrarycorrection amounts at the time of obtaining said correction amount fromsaid input moving image, and conducting n (N≧1) kinds of arbitraryquality improving corrections with respect to said input moving imagebased on the obtained correction amount.
 26. The video processing methodas set forth in claim 21, wherein said correction amount obtaining stepincludes at least one of the steps of: calculating a white balancecorrection amount of said moving image, calculating a contrastcorrection amount of said moving image, calculating a saturationcorrection amount of said moving image, calculating an exposurecorrection amount of said moving image, calculating a sharpnesscorrection amount of said moving image, and calculating a preferablecolor correction amount indicative of a correction amount required for apreset preferable color in said moving image, and said quality improvingcorrection conducting step includes at least one of the steps of:conducting white balance correction of said moving image correspondingto said correction amount obtaining step, conducting contrast correctionof said moving image, conducting saturation correction of said movingimage, conducting exposure correction of said moving image, conductingsharpness correction of said moving image, and conducting saidpreferable color correction of said moving image.
 27. The videoprocessing method as set forth in claim 26, wherein at said qualityimproving correction conducting step, correction is conducted withrespect to a moving image corrected at the step of conducting qualityimproving correction at a preceding stage based on a correction amountcalculated at said step of obtaining a correction amount, and at saidcorrection amount obtaining step, said correction amount is calculatedfrom a moving image corrected at said step of conducting qualityimproving correction corresponding to the step of obtaining a correctionamount at a preceding stage.
 28. The video processing method as setforth in claim 26, further comprising the step of limiting an amount ofchange between the obtained correction amount of a current frame and astored correction amount of a preceding frame.
 29. The video processingmethod as set forth in claim 26, further comprising the steps of:cutting out an evaluation image region necessary for obtaining saidcorrection amount from said frame image, and obtaining said correctionamount from the cut-out evaluation image.
 30. The video processingmethod as set forth in claim 23, further comprising the step of, at thedetection of said cut point, considering a result of comparison of acolor histogram generated based on color information of each pixel ofsaid frame image which is conducted on a frame basis as a feature amountand detecting a cut point of the moving image based on a change of thefeature amount.
 31. The video processing method as set forth in claim30, further comprising the step of, when detecting said cut point, atthe time of generating said color histogram from said frame image,generating said color histogram after thinning out the image at fixedintervals.
 32. The video processing method as set forth in claim 20,further comprising the steps of: when a moving image partly flows onsuch a screen as a screen of a personal computer, before subjecting saidmoving image to correction processing, cutting out a region to becorrected from the moving image in question, subjecting the cut-outimage to be corrected to image correction, and combining said region tobe corrected which is subjected to image correction and a region not tobe corrected which is a remainder left after the region to be correctedin question is cut out to output the combined image.
 33. A videoprocessing method comprising the steps of: obtaining a frame image fromsequentially applied moving images, and detecting a cut point indicativeof switching of a scene in said moving image based on a change of afeature amount obtained from each frame image.
 34. The video processingmethod as set forth in claim 33, wherein at said cut point detectingstep, a result of comparison of a color histogram generated based oncolor information of each pixel of said moving image which is conductedon a frame basis is considered as a feature amount and a cut point ofsaid moving image is detected based on a change of the feature amount.35. The video processing method as set forth in claim 34, wherein atsaid cut point detecting step, at the time of generating said colorhistogram from said moving image, said color histogram is generatedafter thinning out the image at fixed intervals.
 36. A video processingprogram for controlling a computer to execute video processing,comprising the functions of: obtaining at least one correction amountfrom moving images sequentially applied to the computer, comparing theobtained correction amount with a correction amount obtained from atleast one of preceding past frames to suppress a change in correctionamount, and subjecting a frame image to quality improving correctionbased on the suppressed correction amount.
 37. A video processingprogram for controlling a computer to execute video processing,comprising the functions of: obtaining at least one correction amountfrom moving images sequentially applied to the computer, based on achange of a feature amount obtained from a frame image of an inputmoving image, detecting a cut point indicative of switching of a scenein the moving image in question, comparing the obtained correctionamount with a correction amount obtained from at least one of precedingpast frames and suppressing an amount of change in correction amount inconsideration of existence/non-existence of a cut point, and subjectingthe frame image to quality improving correction based on the suppressedcorrection amount.
 38. A video processing program for controlling acomputer to execute video processing, comprising the functions of:obtaining a frame image from sequentially applied moving images, anddetecting a cut point indicative of switching of a scene in said movingimage based on a change of a feature amount obtained from each frameimage.